A few more PS changes (#12552)

# TLDR
Problem-I is a bug fix. The rest are no-ops. 

## Problem I
Page server checks image layer creation based on the elapsed time but
this check depends on the current logical size, which is only computed
on shard 0. Thus, for non-0 shards, the check will be ineffective and
image creation will never be done for idle tenants.

## Summary of changes I
This PR fixes the problem by simply removing the dependency on current
logical size.

## Summary of changes II
This PR adds a timeout when calling page server to split shard to make
sure SC does not wait for the API call forever. Currently the PR doesn't
adds any retry logic because it's not clear whether page server shard
split can be safely retried if the existing operation is still ongoing
or left the storage in a bad state. Thus it's better to abort the whole
operation and restart.

## Problem III
`test_remote_failures` requires PS to be compiled in the testing mode.
For PS in dev/staging, they are compiled without this mode.

## Summary of changes III
Remove the restriction and also increase the number of total failures
allowed.

## Summary of changes IV
remove test on PS getpage http route.

---------

Co-authored-by: Chen Luo <chen.luo@databricks.com>
Co-authored-by: Yecheng Yang <carlton.yang@databricks.com>
Co-authored-by: Vlad Lazar <vlad@neon.tech>

control_plane/src/local_env.rs

@@ -217,6 +217,9 @@ pub struct NeonStorageControllerConf {
     pub posthog_config: Option<PostHogConfig>,
 
     pub kick_secondary_downloads: Option<bool>,
+
+    #[serde(with = "humantime_serde")]
+    pub shard_split_request_timeout: Option<Duration>,
 }
 
 impl NeonStorageControllerConf {
@@ -250,6 +253,7 @@ impl Default for NeonStorageControllerConf {
             timeline_safekeeper_count: None,
             posthog_config: None,
             kick_secondary_downloads: None,
+            shard_split_request_timeout: None,
         }
     }
 }

control_plane/src/storage_controller.rs

@@ -648,6 +648,13 @@ impl StorageController {
             args.push(format!("--timeline-safekeeper-count={sk_cnt}"));
         }
 
+        if let Some(duration) = self.config.shard_split_request_timeout {
+            args.push(format!(
+                "--shard-split-request-timeout={}",
+                humantime::Duration::from(duration)
+            ));
+        }
+
         let mut envs = vec![
             ("LD_LIBRARY_PATH".to_owned(), pg_lib_dir.to_string()),
             ("DYLD_LIBRARY_PATH".to_owned(), pg_lib_dir.to_string()),